Flush tank



FIG. 1 is a perspective view of a flush tank showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a left side elevational view, the right side being a mirrorimage thereof, and;

FIG. 6 is a rear elevational view thereof.

The ornamental design for a flush tank, as shown.